In.sub.0.53 Ga.sub.0.47 As is a potentially attractive material for discrete and integrated optical and microwave device applications. This ternary has the highest mobility among all compositions in the quaternary system InGaAsP which is lattice matched to InP. At high electric field strengths, carrier velocities are expected to be large for the ternary material according to Monte Carlo calculations. Direct measurements have been made of the high field drift velocity of electrons in InGaAs giving values that are larger than the drift velocities in GaAs. Accordingly, very fast devices would be attainable with InGaAs. Many of these devices of the MOS type will require that an oxide layer be grown on InGaAs.
There has been a previous report of a native oxide grown in a lattice matched alloy system using InGaAsP on an InP substrate. This previously reported native oxide was grown by using an anodization process. See the article entitled "Anodic Oxidation of InGaAsP," by H. D. Law Applied Physics Letters, Vol. 37, No. 1, July 1980. In general, anodic oxides of III-V compounds have the following disadvantages: they are hygroscopic, they contain a high density of interface states which renders them useless for electrical devices, and they are mechanically or physically soft so they are easily damaged.